The present invention relates to a ball bearing for longitudinal movements, i.e., linear bearings which have circumferentially distributed inherently closed rows of balls and a sleeve provided with a radial opening for each closed row of balls.
There is known in the art a ball bearing for longitudinal movements, which has a sleeve made of elastic plastic, in which there are snap-fastened in the area of the load-bearing balls of each enclosed row of balls angularly movable steel traveller plates inside radial apertures of the sleeve. This known ball bearing is attended by the drawback that the track of the steel traveller plates, on account of their angular mobility in longitudinal direction, continuously changes its position as a function of the bearing load and speed, so that the extremities of said track are not aligned with the extremities of the respective non-angularly movable deflection track of the sleeve. As a result, the balls abut shock-like at the transition point between the track and the deflector track at the edges of said tracks, being exposed there to a damaging wear as a result of the contacting. A similar drawback is inherent in the axial mobility of the steel traveller plates that are mounted into the sleeve with little axial play; as a result of said axial play, there is caused in the ball bearing, gaps or cleavages between the axial track of the load-bearing balls and the deflection track, which impair the rolling and moving of the balls. Moreover, during manufacture it is necessary to maintain close tolerances with regard to the individual steel traveller plates of a given bearing in view of the fact that said traveller plates may have only very small deviations in their wall thicknesses. As a result, manufacturing of the bearing is rendered more difficult and expensive.
It is the object of the invention to create a linear ball bearing for longitudinal movements, which obviates these drawbacks.